The invention relates to a moving ramp intended e.g. for transportation of people, comprising plates supported by wheels, which are guided for movement at an upper level to form the loaded part of the moving ramp, and at a lower level which is substantially parallel with the upper level, to form the returning part of the moving ramp adjacent plates in each part being close to each other, wherein stationary guides are provided as upper and lower runway tracks for the wheeled plates, the plates at the edges thereof are pivotally connected to endless chains at one end of the plates said chains extending along the parts to be driven in one direction in the upper part and in the opposite direction in the lower part, the other end of the plates being free for angular adjustment in cooperation with guides at the ends of the moving ramp to lower and raise, respectively, the plates by vertical displacement thereof in a substantially horizontal position one at the time from one part to the other.
U.S. Pat. No. 3,447,666 describes a moving ramp of this kind wherein the chains move in a substantially rectangular path, turning sprockets being provided at the four corners of the rectangle, and wherein a transition portion of each chain between the upper part and the lower part being utilized to transfer the end of the plates which is connected to the chain, from the upper part to the lower part, and vice versa. For the transfer of the free end of the plates there is provided at each end of the moving ramp endless auxiliary chains which are also guided in a rectangular path over turning sprockets in the four corners of the rectangle, vertical transfer portions being provided in parallel with the transition portions to take care of the free end of the plates and transfer this end from the upper part to the lower part, and vice versa, the plates being guided for parallel movement.
In another prior art moving ramp according to U.S. Pat. No. 2,893,538 wherein no endless chains are provided and wherein the plates are guided on upper and lower guide rails in the supporting and returning part, respectively, the plates are driven by means of gear wheels engaging racks on the plates in the upper part as well as the lower part. The plates are transferred between the parts at the two ends of the moving ramp by means of synchronously driven arms engaging the plates at the two ends thereof to transfer the plates by a parallel movement between the parts.
These prior art devices necessitate a large construction height in order that means provided for the transfer of the plates from one part to the other at the ends of the endless chains and for advancing the plates in the upper and lower parts will function in a satisfactory way.
If it is necessary to have the loaded part located substantially at the level of the supporting floor structure a substantial space must be provided below the loaded part to receive the returning part and the driving machinery, which means that the floor structure must form a "ditch" providing the necessary space.